I fill the gas tank because I monitor the fuel gauge, not because it warns me that it's nearly empty.

Using an appropriate analogy to make something clearer works better than shoehorning something to push your view.

I plug my laptop to charge the battery when convenient and operate in a geographical area where power shortages are still an exception so I have no fuel issue in my computer usage whether I use automatic system update or not.

Actually I do not use automatic system update, if there is such a thing for this OS, it is discouraged as updates can sometimes break the system if applied blindly.

How exactly can someone not applying updates when windows asks for it put everyone else at risk ? What risk do I face from this from behind my BSD firewall on an Arch linux powered computer ?

Then again my experience of windows computers since windows update was introduced is not in line with what you describe here, getting even worse in recent times with updates applying themselves with little to no warning, sometimes running several times in a row: logs you out of your computer, applies updates for 10-45 minutes, reboots, applies updates for 15-60 minutes, logs you in, crawls your computer down by downloading more updates, logs you out of your computer, applies update for 10-45 minutes, etc...

I've witnessed this happens 3 times in a single week, the owner of the computer was pissed, I'm paid by the hour and happily browsed the web on my linux laptop while the client pestered against his computer, microsoft, technology, corporations, politicians allowing this to happen and so on.